Engine breather hole

[Adamastor]

Hi there!

I was wondering... does the R65 have these drain holes?

Regards,

Sergio

[Barry]

Can't say I've ever seen it for real but that looks to me like the drain hole associated with the engine breather for allowing condensed vapour to drain back into the crankcase. Later bikes are supposed to have this so that should include the R65.  I've been meaning to take a look to make sure it isn't blocked and also to check the breather pipes are clear. A job to do when the fuel rank runs low.

[Bob_Roller]

I've never seen a cutaway of the engine case of an R65 engine .

The engine has a breather valve on top, under the cover over the starter .

Been a while since I've been in there, can't say for sure if it has any return drain holes or not .

[Adamastor]

I Just checked mine, it doesnt... the breather itself is of the reed type (the newer) but the breather cap is small, has only two bolts (the ones with drain hole are supposed to have three) and no drain hole.
It is a pitty because I still have high oil consumption and was looking for another reason to justify it..

[Bob_Roller]

Is there oil dripping out of the carbs, another source of oil consumption, is the crankcase breather .

There is a fair amount of atomized oil coming out of the breather, and it goes right into the carb intake 'horns' inside the airbox .

I read in the Airheads Beemer Club monthly newsletter about 15 years ago, that adding a small portion of a copper pot scrubbing pad to the cavity area above the reed valve in the breather housing, would reduce oil consumption, as the atomized oil can collect on the copper pad, and get returned to the oil sump, instead of being drawn into the intake system, or puddle in the airbox .

Other members here have mentioned, that if they keep topping off the oil quantity to the full mark, the bike seems to consume more than a normal  amount of oil .

Try keeping the oil level at the mid-way between full and add, and see if that helps reduce the oil consumption .

[Adamastor]

Hmmm interesting that mod. Last sunday I have done a 300miles ride and my oil dipstick went from middle to minimum (that's about half a litter).
It is a very high consumption, almost like a 2T engine. I am doing the piston rings break-in, could it be the only reason for this? Another weird thing was that, the first half of the ride the consumption was very low (I checked the oil level at middle of the ride just to be safe, and it was just a little bellow middle).
Some parts of the ride were a bit hilly, can this explain all this consumption?

Many regards and thanks for helping on my unstoppable wave of questions Learning is good ehe

I will post some photos of the ride so I can pay back a bit

Sergio

[Adamastor]

Hmmm, I do see oil goes to the carburator inlet, I really cant quantify if it is too much, maybe it is.
Can you please explain me better (or do you have any link) how that copper mod works?
Thanks
And here a link to the ride photos:
 http://www.bmwr65.org/cgi-bin/yabb2/YaBB.pl?num=1269290170

[Bob_Roller]

Don't have link, as it was explained in the article, the air coming out of the breather valve, contains a fine mist of oil, with the copper pad installed, the air goes through the pad, and the oil mist collects on the strands of copper, and then when enough collects, it runs down to the breather valve, and then seeps back into the oil sump when the engine is shut down .

There may be a slight vacuum develop in the crankcase when the engine cools off, and the oil is drawn back into the engine via the breather system .

But that's only a guess !!!

[Adamastor]

Could this be a copper pad like those used on electronic kits:



Sergio

[Bob_Roller]

No, what was called out for in the article, was a common pot scrubbing pad made of shredded copper a lot coarser 'strands' than steel wool, used to clean dishes, and cooking pots .

You get them at a grocery store or similar retail outlet .

[montmil]

On the Airheads Beemer Club list, I recall -I think, anyway- that some peeps were modifying the crankcase breather system in a way to eliminate the oil mist entering the carbs. I'm considering doing the same thing with some tubing and a small, concealed catch can.

Fairly common on hotrod engines / aircraft engine installs I've seen.

Monte

[Adamastor]

I just found this:
For an old Airhead, greater than 2000 miles per quart.
For a bike with new rings that isn't been broken in yet, greater than 500 miles per quart.
in here:
http://www.bmwscotter.com/topics/engine_oil/engine_oil.htm#normal_oil_consumption

And got bit less worried about the oil consumption... maybe it's just normal consumption related to new rings. Nikasil cylinders make for a long time break-in, right?

Regards,

Sergio

[Barry]

Going back to your original picture of the drain hole.

I think it is item 22 and I'm not sure you would be able to see it easily.

[Adamastor]

Hi Barry, the hole is located on a cavity under the breather valve case. It only exists on some models, mine only has the breather valve under the case and it is quite small..
Anyone knows if it is located in some other place?

[Barry]

Adamastor

The oil diagram came from this document originally published in early 1979. It describes the breather function and return of condensed oil vapour via that drain hole

http://www.omnilex.com/public/bmw78/boxloob.pdf